APPLICATION
2.7 LCD drive control circuit
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3825 GROUP USER’S MANUAL
Table 2.7.2 Pin functions by setting the corresponding registers when they are not used as seg-
ment output pins
Ports
PULLA (Address 001616) b0
(Bit 0 of PULL register A)
Setting
Register
Value
Pin function
P30–P37
P1C (Address 000316) b0
(Bit 0 of port P1 output control register)
PULLA (Address 001616) b0
(Bit 0 of PULL register A)
PULLA (Address 001616) b0
(Bit 0 of PULL register A)
P10–P15
P00–P07
0
No pull-down
Pull-down pin
(When bit 0 of P1C is “0”)
1
0
Output port function is invalid
1
Output port
No pull-down
(When being set for output mode)
0
Pull-down pin
Output function is invalid
1
0
No pull-down
(When being set for output mode)
1
Pull-down pin
Output function is invalid
Pins
(1) Segment output pins (SEG0–SEG39)
Up to 40 segment outputs can be selected. Table 2.7.3 shows setting of segment output pins for LCD
display.
Table 2.7.3 Setting of segment output pins for LCD display
SEG0–SEG17
Segment output-only pin
Setting
Ports P30–P35 are used as segment signal output pins (SEG18–SEG23) by setting
bit 0 of the segment output enable register (address 003816) to “1.”
Ports P36 and P37 are used as segment signal output pins (SEG24, SEG25) by setting
bit 1 of the segment output enable register (address 003816) to “1.”
Ports P02–P05 are used as segment signal output pins (SEG26–SEG31) by setting
bit 2 of the segment output enable register (address 003816) to “1.”
Ports P06 and 07 are used as segment signal output pins (SEG32, SEG33) by setting
bit 3 of the segment output enable register (address 003816) to “1.”
P10/SEG34
Port P10 is used as segment signal output pins (SEG34) by setting bit 4 of the segment
output enable register (address 003816) to “1.”
Ports P11–P15 are used as segment signal output pins (SEG35–SEG39) by setting
bit 5 of the segment output enable register (address 003816) to “1.”
P30/SEG18–
P35/SEG23
P36/SEG24,
P37/SEG25
P00/SEG26–
P05/SEG31
P06/SEG32,
P07/SEG33
P11/SEG35–
P15/SEG39